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Biomedical subjects

M Reeves

Publications and source records attributed to M Reeves.

At least 19 recordsLinked to original sources
PubMed1999

Epidemic serogroup B meningococcal disease in Oregon: the evolving epidemiology of the ET-5 strain.

CONTEXT: In 1993, Oregon's incidence of serogroup B meningococcal disease began to rise because of a highly clonal group of strains designated enzyme type 5 (ET-5), the first such increase observed in the United States. OBJECTIVE: To evaluate the impact that the ET-5 strain has had on the epidemiology of meningococcal disease in Oregon. DESIGN AND SETTING: Epidemiologic analysis of surveillance data on Oregon meningococcal disease cases from 1987 through 1996 and multilocus enzyme electrophoresis typing of serogroup B isolates from June 1993 through April 1995 and from April through June 1996. PATIENTS: A total of 836 persons with invasive meningococcal disease. MAIN OUTCOME MEASURES: Disease frequency and clonality of strains. RESULTS: Serogroup B disease incidence rates more than doubled from the preepidemic period in 1987-1992 (1.0 case per 100000 population) to the recent epidemic period in 1995-1996 (2.2 cases per 100000). The age-specific incidence rate of serogroup B disease among those 15 through 19 years old increased 13-fold between the preepidemic period (0.5 case per 100000) and 1995-1996 (6.4 cases per 100000). However, the proportion of cases with meningococcemia and the case-fatality rate did not change. Of 99 Neisseria meningitidis isolates obtained from 1993-1995, 88 (89%) belonged to the ET-5 complex. Of these, 69 (78%) were a single clone, designated 301. Of 20 serogroup B isolates from 1996, 18 (90%) belonged to the ET-5 complex; 17 (94%) were the 301 clone. CONCLUSION: Serogroup B meningococcal disease incidence continues at high levels in Oregon with increasing predominance of the ET-5 clonal strains.

Adolescent↗
PubMed1999

Characterization and partial purification of CD34+ progenitor cell ecto-phosphatidic acid phosphohydrolase.

Phosphatidic acid and its hydrolysis product, diacylglycerol, play potentially vital roles as extracellular messengers in numerous cellular systems and may play a key role in regulating hematopoiesis. In this study, we describe an ecto-phosphatidic acid phosphohydrolase that potentially regulates cellular responses to phosphatidic acid on bone marrow derived human hematopoietic progenitors. We partially purified hematopoietic progenitor ecto-PAPase using a novel in-gel phosphatase assay and then characterized the enzyme on phenotypically defined subpopulations of hematopoietic CD34+ progenitors isolated by flow cytometry. The most pronounced PAPase activity was confined to uncommitted CD34+/CD38+ hematopoietic progenitors, which lacked the expression of other lineage-associated antigens. We conclude that hematopoietic progenitor cells at various stages of maturation possess a potent ecto-PAPase, an enzyme well positioned to regulate progenitor cell growth and differentiation induced by phosphatidic acid and related lipids.

Antigens, CD34↗
PubMed1999

Use of molecular subtyping to document long-term persistence of Corynebacterium diphtheriae in South Dakota.

Enhanced surveillance of patients with upper respiratory symptoms in a Northern Plains community revealed that approximately 4% of them were infected by toxigenic Corynebacterium diphtheriae of both mitis and gravis biotypes, showing that the organism is still circulating in the United States. Toxigenic C. diphtheriae was isolated from five members of four households. Four molecular subtyping methods-ribotyping, multilocus enzyme electrophoresis (MEE), random amplified polymorphic DNA (RAPD), and single-strand conformation polymorphism-were used to molecularly characterize these strains and compare them to 17 archival South Dakota strains dating back to 1973 through 1983 and to 5 isolates collected from residents of diverse regions of the United States. Ribotyping and RAPD clearly demonstrated the household transmission of isolates and provided precise information on the circulation of several distinct strains within three households. By MEE, most recent and archival South Dakota strains were identified as closely related and clustered within the newly identified ET (electrophoretic type) 215 complex. Furthermore, three recent South Dakota isolates and eight archival South Dakota isolates were indistinguishable by both ribotyping and RAPD. All of these molecular methods showed that recent South Dakota isolates and archival South Dakota isolates were more closely related to each other than to the C. diphtheriae strains isolated in other parts of the United States or worldwide. The data also supported the improbability of importation of C. diphtheriae into this area and rather strongly suggest the long-term persistence of the organism in this region.

Bacterial Typing Techniques↗
PubMed1997

Topographic associations between DNA fragmentation and Alzheimer's disease neuropathology in the hippocampus.

To identify whether the process of apoptosis bears a topographic relationship to selected aspects of Alzheimer's disease (AD) pathology, we used an in situ nick translation method (TUNEL) to map DNA fragmentation in hippocampal sections immunostained for abnormally phosphorylated tau, which exists in the neurofibrillary tangles (NFTs) and in the dystrophic neurites associated with senile plaques. To ascertain associations of DNA fragmentation with glia, TUNEL was combined with immunohistochemistry for the astrocyte marker, glial fibrillary acidic protein (GFAP), or the microglial antigen OX-42. Consistent with previous reports, the incidence of putative DNA fragmentation detected by TUNEL was much higher in the AD brain, compared to non-demented subjects. While most TUNEL-positive cells did not exhibit any systematic topographic relationship to senile plaques, which were visualized by immunostain of abnormally phosphorylated tau for dystrophic neurites, DNA fragmentation was found frequently within cells containing NFTs. In hippocampal sections prepared to visualize glia, DNA fragmentation was not observed in GFAP-positive astrocytes, but some OX-42-positive microglia exhibited TUNEL signals. Other TUNEL-positive cells were found frequently in proximity to glia. The data suggest that cells compromised by the deposition of NFTs are prone to initiate the process of apoptosis. Furthermore, some glial populations appear to be apoptotic in the AD brain.

Aged↗
PubMed1997

The value of simulations in the management education of nurses: students' perceptions.

This paper examines the use of simulations in the education of student nurses as part of their preparation for management responsibility. A review of the literature indicates that there is little published work on this topic and that those evaluations that have been reported invariably occur at the end of the exercise, thus giving an incomplete picture of the simulation. The nature and format of the simulation, used with 128 students undertaking a pre-registration/diploma in higher education course, is described. Results from student evaluations immediately following the exercise and after 13 weeks of clinical experience are presented. The findings indicate that this is a realistic and enjoyable way of learning which adequately prepares students for management experience in subsequent clinical allocations. Issues concerned with internal and external validity of simulations and areas for further research are explored.

Attitude of Health Personnel↗
PubMed1997

Molecular epidemiology of sporadic (endemic) serogroup C meningococcal disease.

Understanding the basis of sporadic (endemic) meningococcal disease may be critical to prevention of meningococcal epidemic outbreaks and to understanding fluctuations in incidence. Active, prospective, population-based surveillance and molecular epidemiologic techniques were used to study sporadic serogroup C meningococcal disease in a population of 2.34 million persons (Atlanta area). During 1988-1994, in which no outbreaks or case clusters were reported, 71 patients developed sporadic serogroup C meningococcal disease (annual incidence, 0.51/100,000). Eighty-three percent of patients were >2 years old. By multilocus enzyme electrophoresis, pulsed-field gel electrophoresis, and serotyping, 84% (52/62) of the isolates available for study were identical or closely related members of the electrophoretic type 37 (ET 37) complex responsible for multiple serogroup C outbreaks in the United States in the 1990s. Sporadic disease caused by 9 clonal strains occurred over periods up to 4 years and accounted for 45% (28/62) of cases. Sporadic serogroup C meningococcal disease was most often due to a limited number of related strains that appear to slowly circulate in the population.

Adolescent↗
PubMed1996

Axonal interactions regulate Schwann cell apoptosis in developing peripheral nerve: neuregulin receptors and the role of neuregulins.

Programmed cell death during development resulting from the lack of appropriate survival factors has been demonstrated in both neurons and oligodendrocytes and occurs mostly in the form of apoptosis. We now demonstrate that Schwann cells in the rat sciatic nerve undergo apoptosis during early postnatal development and that the amount of apoptosis is markedly increased by axotomy. The apoptotic Schwann cells express the low-affinity nerve growth factor receptor but not myelin-related proteins, indicating that they are in the premyelinating state. Apoptosis resulting from normal development or from axotomy can be inhibited markedly by exogenous neuregulin. Consistent with this, the neuregulin receptor components erbB2 and erbB3 are expressed and phosphorylated in developing sciatic nerve. These data suggest that Schwann cell number in developing peripheral nerve is regulated by apoptosis through competition for axonally derived neuregulin.

Aging↗
PubMed1996

The utilization and evaluation of a simulation game in pre-registration nurse education.

The employment of simulations and games has been widely recommended for use in nurse education but there are few reports of their introduction or evaluation. This paper describes the use and evaluation of a simulation game which prepares students for a management module in an English National Board pilot scheme course. Evaluation took place by using a questionnaire completed by 528 students and by participant observation by the facilitators. The evaluation indicates that a simulation game is an appropriate way of preparing students for practice and that it provides a realistic and safe environment for enjoyable and meaningful learning to take place.

Games, Experimental↗
PubMed1996

Long-term survival in advanced chronic myelogenous leukemia following bone marrow transplantation from haploidentical related donors.

From 1987 to 1991, 26 patients with CML and a median age of 31 years received allogeneic BMT from a partially mismatched related donor (PMRD) who shared at least one haplotype with the recipient. Nine patients were in accelerated phase (AP), and 11 patients were in blast crisis (BC) at the time of BMT. Patients were mismatched either in graft-versus-host or host-versus-graft directions for one antigen in 3 patients, two antigens in 14 patients, and three antigens in 9 patients. All patients were prepared with a regimen consisting of total body irradiation, etoposide, cytosine arabinoside, cyclophosphamide and methylprednisolone. All marrows were treated ex vivo with T10B91.A-31, a monoclonal antibody directed toward the alpha beta heterodimer of the CD3 receptor, and rabbit complement. Additional GVHD prophylaxis included either the anti-CD5 immunoconjugate XomaZyme-H65, cyclosporine, or both in combination with methylprednisolone. Eight patients did not have sustained engraftment. The 100-day survival was 42%. The incidence of > or = grade II acute GVHD was 29%. The incidence of chronic GVHD was 50% and was limited in all cases. The median survival at 4 years for all 26 patients was 27%. Seven patients (CP 1, AP 3, BC 3) remain in hematologic remission 1297-2241+ days after transplantation. AlloBMT from a PMRD may be considered for patients with advanced CML who lack a matched sibling or unrelated donor.

Adolescent↗
PubMed1994

Biosorption of nickel in complex aqueous waste streams by cyanobacteria.

A study was undertaken to determined if a suitable biosorbent could be found for removal of nickel at low concentrations (< 20 parts per million [ppm]) from a chemically complex wastewater effluent generated by electroplating operations. Algae and cyanobacteria were chosen as candidate biosorbent materials because they are easy to grow and they have the ability to withstand processing into biosorbent materials. Several species were screened for nickel-biosorption capacity initially, and three species of cyanobacteria were selected for further study based on their performance in the scoping tests. When compared to live controls, autoclaving improved the binding capacities of all three species, but usually biosorption data from experiments with live cells were more consistent. None of the three species was able to bind nickel efficiently in actual effluent samples. Further experimentation indicated that sodium ions, which were present in high concentrations in the effluent, were interfering with the ability of the cells to bind nickel. Adsorption isotherm plots for biosorption of nickel by two species of Anabaena in NiCl2-deionized water solutions were prepared.

Adsorption↗
PubMed1993

Serum urea nitrogen and conception rate: the usefulness of test information.

Total of 627 AI in 332 Holstein cows in nine herds were used to examine the relationship between serum urea N and conception rate. Cows were assigned randomly to one of three isocaloric diets varying in protein degradability and content. The AI occurred from 50 to 150 DIM. Mean serum urea N for each cow from 50 to 150 DIM was used to examine conception rate and serum urea N. The clinical interpretation of serum urea N on conception rate is evaluated using Bayes theorem from two approaches (dichotomization vs. continuous). Test information resulting from dichotomization of serum urea N into high and low categories (maximizing the average of test sensitivity and specificity) is compared with likelihood ratio approaches allowing a continuous measure. Likelihood ratio test indicates that conception rate decreases with serum urea N of > 14.9 mg/dl, but dichotomized test suggests that the decrease does not occur until serum urea N is > 20 mg/dl.

Animals↗
PubMed1992

Role of foods in sporadic listeriosis. II. Microbiologic and epidemiologic investigation. The Listeria Study Group.

OBJECTIVE: To evaluate the role of foods in sporadic listeriosis. DESIGN: Microbiologic survey of foods collected from refrigerators of patients with listeriosis identified through active laboratory-based surveillance. Patient and food Listeria monocytogenes isolates were subtyped to identify foods contaminated with the same strain of L monocytogenes that caused illness in the patient; samples of these foods were obtained from the retail source. SETTING: Multistate population-based study conducted between 1988 and 1990. RESULTS: Listeria monocytogenes grew from at least one food specimen in the refrigerators of 79 (64%) of 123 listeriosis patients; 11% of more than 2000 food specimens collected in the study contained L monocytogenes. Twenty-six (33%) of 79 refrigerators with foods that grew L monocytogenes contained at least one food isolate of the same strain as that in the corresponding patient, a frequency much higher than would be expected by chance (P less than .001). Multivariate analysis showed that of the food specimens that grew L monocytogenes, foods that were ready-to-eat, foods that grew L monocytogenes by a direct-plating method (a measure of the level of contamination), and foods that contained serotype 4b isolates were independently associated with an increased likelihood of containing the patient-matching strain. CONCLUSION: We identified specific food and L monocytogenes isolate characteristics--ready-to-eat foods, foods containing higher concentrations of L monocytogenes, and foods containing serotype 4b--which were associated with disease-causing strains. These results can provide guidance to industry and regulatory agencies in developing strategies to prevent listeriosis.

Food↗
PubMed1992

Epidemic meningococcal disease in Nairobi, Kenya, 1989. The Kenya/Centers for Disease Control (CDC) Meningitis Study Group.

An epidemic of meningococcal disease occurred in Nairobi, Kenya, during 1989, outside the "meningitis belt" of sub-Saharan Africa. About 3800 cases occurred between April and November (250/100,000 population). The case-fatality rate was 9.4% among hospitalized patients. Areas that included Nairobi's largest slums had particularly high attack rates. The epidemic displayed an unusual age distribution, with high attack rates among those 20-29 years old. A vaccination campaign was conducted. By early January, the weekly case count had fallen to 25 from a high of 272 (in September). A case-control study estimated the vaccine efficacy to be 87% (95% confidence interval, 67%-95%). A model estimated that the vaccination campaign reduced the number of cases by at least 20%. Multilocus enzyme electrophoretic typing demonstrated that the strain responsible for this large epidemic is closely related to strains that caused other recent epidemics, documenting further spread of what may be a particularly virulent clonal complex of group A Neisseria meningitidis.

Adolescent↗